Direct drive unit removal system and associated methods

ABSTRACT

Described herein are embodiments of systems and methods for the removal of a direct drive unit (DDU) housed in an enclosure, such as a direct drive turbine (DDT) connected to a gearbox for driving a driveshaft connected to a pump for use in a hydraulic fracturing operations.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Non-Provisional applicationSer. No. 15/929,924, filed May 29, 2020, titled “DIRECT DRIVE UNITREMOVAL SYSTEM AND ASSOCIATED METHODS,” which claims the benefit of andpriority to U.S. Provisional Application No. 62/899,975, filed Sep. 13,2019, titled “TURBINE REMOVAL SYSTEM,” the entire disclosures of each ofwhich are incorporated herein by reference.

BACKGROUND OF THE DISCLOSURE

This disclosure relates to embodiments of systems and methods for theremoval and/or positioning of a direct drive unit housed in anenclosure, such as a direct drive turbine (DDT) when connected to agearbox for driving a driveshaft, which, in turn, may be connected to apump such as for use in a hydraulic fracturing system.

Traditional fracturing pumping fleets have had fuel supplied from asingle fuel source. In such units, when a unit runs low on fuel (forexample diesel), that unit is shutdown while another stand by unit isbrought in, refueled, and then put into service. Some inefficienciesincluded in this process are that the unit once low on primary fuel mustbe stopped, refueled while another unit is simultaneously beingintroduced into its place to make up for the loss of the pumping powerthat the unit provides. This may affect the pumping performance during asection as well as requiring human intervention to perform therefueling, lining up suction and discharge valves. This may requiremultiple personnel to relay back the information so the process isperformed in the correct series of steps. Using a single fuel sourcealso limits the ability for the fracturing fleet to make it continuouslythrough a section when low on fuel which results in delays in pumpingcompletion.

In addition, in cases where the unit needs to be taken offline formaintenance or replacement, significant disassembly is required toremove the unit from its enclosure and to install a replacement unit,potentially resulting in excessive downtime. In some cases, the entiretrailer and enclosure need to be removed from the site so a new, fullyequipped trailer may be moved into place.

Accordingly, it may be seen that a need exists for more efficient waysof accessing the drive units for maintenance purposes and/or replacementwith minimum disruption to the system operations and the surroundingequipment. The present disclosure addresses these and other related andunrelated problems in the art.

SUMMARY OF THE DISCLOSURE

According to one embodiment of the disclosure, a method of removing adirect drive unit (DDU) housed in an enclosure. The DDU includes agearbox and a turbine engine connected to the gearbox for driving adriveshaft connected to a pump for use in high-pressure, high-powerhydraulic fracturing operations. The method may include accessing theenclosure. The enclosure contains air inlet ducting connected to theturbine engine and air exhaust ducting connected to the turbine engine.The method may further include disconnecting the turbine engine from theair inlet ducting, disconnecting the turbine engine from at least onefuel line, disconnecting the gearbox from the driveshaft, disconnectingthe turbine engine from an at least one exhaust flange connected to theair exhaust ducting, and operating a DDU positioner assembly to positionthe DDU for withdrawal from the enclosure, and removing the DDU from theenclosure.

According to another embodiment of the disclosure, a direct drive unit(DDU) positioner assembly is disclosed for positioning a DDU housed inan enclosure for removal from the enclosure. The DDU includes a gearboxand a turbine engine connected to the gearbox for driving a driveshaftconnected to a pump for use in high-pressure, high-power hydraulicfracturing operations. The DDU positioner assembly may include aplurality of longitudinal rails extending in a longitudinal directionalong the central axis of the DDU and a plurality of lateral railsextending in a lateral direction transverse to the longitudinaldirection. The DDU positioner assembly may further include a platformslidably connected to the plurality of lateral rails. The plurality oflongitudinal rails may be mounted on the platform and the DDU may beslidably connected to the longitudinal rails. The DDU may be movable inthe longitudinal direction along the longitudinal rails and the platformmay be movable in the lateral direction along the lateral rails.

According to yet another embodiment of the disclosure, a direct driveunit (DDU) positioner assembly is disclosed for positioning a DDU housedin an enclosure for removal from the enclosure. The DDU includes agearbox and a turbine engine connected to the gearbox for driving adriveshaft connected to a pump for use in high-pressure, high-power,hydraulic fracturing operations. The DDU positioner assembly may includea platform connected to a support of the gearbox and mounted on anenclosure base of the enclosure. The enclosure base may have a pluralityof lubrication grooves for facilitating sliding movement of the platformrelative to the enclosure base. The DDU positioner assembly may includea lubricator to convey lubricant to the lubrication grooves. Theplatform may be fixedly attached to the enclosure base by one or morefasteners during operation of the DDU and in slidable engagement withthe enclosure base upon removal of the one or more fasteners.

Those skilled in the art will appreciate the benefits of variousadditional embodiments reading the following detailed description of theembodiments with reference to the below-listed drawing figures. It iswithin the scope of the present disclosure that the above-discussedaspects be provided both individually and in various combinations.

BRIEF DESCRIPTION OF THE DRAWINGS

According to common practice, the various features of the drawingsdiscussed below are not necessarily drawn to scale. Dimensions ofvarious features and elements in the drawings may be expanded or reducedto more clearly illustrate the embodiments of the disclosure.

FIG. 1A is a schematic diagram of a pumping unit according to anembodiment of the disclosure.

FIG. 1B is a schematic diagram of a layout of a fluid pumping systemaccording to an embodiment of the disclosure.

FIG. 2 is a perspective view of an enclosure for housing a direct driveunit (DDU) according to an embodiment of the disclosure.

FIG. 3 is a top plan view of the enclosure housing the DDU according toan embodiment of the disclosure.

FIG. 4 is a side elevation view of the DDU mounted on a DDU positionerassembly according to a first embodiment of the disclosure.

FIG. 5 is an end elevation view of the DDU of FIG. 4 according to afirst embodiment of the disclosure.

FIG. 6A is a perspective view of the DDU of FIG. 4 in a first positionaccording to a first embodiment of the disclosure.

FIG. 6B is a perspective view of the DDU of FIG. 6A moved to a secondposition according to a first embodiment of the disclosure.

FIG. 6C is a perspective view of the DDU of FIG. 6B moved to a thirdposition according to a first embodiment of the disclosure.

FIG. 7 is a side elevation view of the DDU mounted on a DDU positionerassembly according to a second embodiment of the disclosure.

FIG. 8A is a perspective view of the DDU of FIG. 7 in a first positionaccording to a second embodiment of the disclosure.

FIG. 8B is a perspective view of the DDU of FIG. 8A moved to a secondposition according to a second embodiment of the disclosure.

FIG. 8C is a perspective view of the DDU of FIG. 8B moved to a thirdposition according to a second embodiment of the disclosure.

FIG. 9 is an enlarged detail of a portion of the DDU positioner assemblyaccording to a second embodiment of the disclosure.

FIG. 10 is a detail of a portion of the DDU positioner assemblyaccording to a second embodiment.

FIG. 11 is a side elevation view of the DDU mounted on a DDU positionerassembly according to a third embodiment of the disclosure.

FIG. 12A is a perspective view of the DDU of FIG. 11 in a first positionaccording to a third embodiment of the disclosure.

FIG. 12B is a perspective view of the DDU of FIG. 12A moved to a secondposition according to a third embodiment of the disclosure.

FIG. 12C is a perspective view of the DDU of FIG. 12B moved to a thirdposition according to a third embodiment of the disclosure.

Corresponding parts are designated by corresponding reference numbersthroughout the drawings.

DETAILED DESCRIPTION

Generally, this disclosure is directed to a direct drive unit (DDU)positioner assembly, positioning system, removal system, and/orassociated mechanisms that will allow a DDU including a gearbox and aturbine engine connected to the gearbox to be detached from surroundingequipment and removed through the side of an enclosure housing thedirect drive unit. The system will allow for inspections, maintenance,or even a complete exchange of the direct drive unit with another ifnecessary.

FIG. 1A illustrates a schematic view of a pumping unit 11 for use in ahigh-pressure, high power, fluid pumping system 13 (FIG. 1B) for use inhydraulic fracturing operations according to one embodiment of thedisclosure. FIG. 1B shows a typical pad layout of the pumping units 11(indicated as FP1, FP2, FP3, FP4, FP5, FP6, FP7, FP8) with the pumpingunits all operatively connected to a manifold M that is operativelyconnected to a wellhead W. By way of an example, the system 13 is ahydraulic fracturing application that may be sized to achieve a maximumrated horsepower of 24,000 HP for the pumping system 13, including aquantity of eight (8) 3000 horsepower (HP) pumping units 11 that may beused in one embodiment of the disclosure. It will be understood that thefluid pumping system 13 may include associated service equipment such ashoses, connections, and assemblies, among other devices and tools. Asshown in FIG. 1, each of the pumping units 11 are mounted on a trailer15 for transport and positioning at the jobsite. Each pumping unit 11includes an enclosure 21 that houses a direct drive unit (DDU) 23including a gas turbine engine 25 operatively connected to a gearbox 27.The pumping unit 11 has a driveshaft 31 operatively connected to thegearbox 27. The pumping unit 11 includes a high-pressure, high-power,reciprocating positive displacement pump 33 that is operativelyconnected to the DDU 23 via the driveshaft 31. In one embodiment, thepumping unit 11 is mounted on the trailer 15 adjacent the DDU 23. Thetrailer 15 includes other associated components such as a turbineexhaust duct 35 operatively connected to the gas turbine engine 25, airintake duct 37 operatively connected to the gas turbine, and otherassociated equipment hoses, connections, etc. to facilitate operation ofthe fluid pumping unit 11.

In the illustrated embodiment, the gas turbine engine 25 is a VericorModel TF50F bi-fuel turbine; however, the direct drive unit 23 mayinclude other gas turbines or suitable drive units, systems, and/ormechanisms suitable for use as a hydraulic fracturing pump drive withoutdeparting from the disclosure. The gas turbine engine 25 is cantilevermounted to the gearbox 27 with the gearbox supported by the floor 41 ofthe enclosure 21. The gearbox 27 may be a reduction helical gearbox thathas a constant running power rating of 5500 SHP and intermittent poweroutput of 5850 SHP, or other suitable gearbox. It should also be notedthat, while the disclosure primarily describes the systems andmechanisms for use with direct drive units 23 to operate fracturingpumping units 33, the disclosed systems and mechanisms may also bedirected to other equipment within the well stimulation industry suchas, for example, blenders, cementing units, power generators and relatedequipment, without departing from the scope of the disclosure.

FIG. 2 illustrates the enclosure 21 that houses the direct drive unit 23in an interior space 46 of the enclosure. In one embodiment, theenclosure has access doors 45 for removal of the DDU 23 from theenclosure and/or other components within the enclosure. The enclosure 21provides sound attenuation of the DDU 23 during operation.

As shown in FIG. 3, the direct drive unit 23 and the enclosure 21 has alongitudinal axis L1 and a lateral axis L2 transverse to thelongitudinal axis. FIG. 3 illustrates a top view of the enclosure 21with the DDU 23 shown attached to the driveshaft 31 that extends throughan opening 48 in a first longitudinal end 47 of the enclosure. An airexhaust assembly 35 extends through a second longitudinal end 49 of theenclosure. The DDU 23 has a central axis CL extending in thelongitudinal direction L1 that extends through the centerline of theunit and is aligned with the centerline of the driveshaft 31. Thegearbox 27 includes an outlet flange 50 that is connected to thedriveshaft 31. The gas turbine engine 25 has two air inlet ports 51, 53on a respective lateral side of the central axis CL and an exhaust ductflange 54 that connects the gas turbine engine to the air exhaustassembly 35 at the longitudinal end 49 of the enclosure 21. In oneembodiment, the access doors 45 are mounted on a first lateral side 55of the enclosure 21, but the enclosure may have additional access doorson a second lateral side 57 of the enclosure, or the access doors may bepositioned only on the second lateral side without departing from thescope of this disclosure. The gas turbine engine 25 may include polymerexpansion joints 61, 63 connected to air inlet ports 51, 53, tofacilitate the removal of the gas turbine engine from the enclosure 21.The gas turbine engine 25 may include various fuel lines, communicationlines, hydraulic and pneumatic connections, and other connections oraccessories needed for operation of the gas turbine engine withoutdeparting from the disclosure. Such connections may utilize quickdisconnect fittings and check valves to facilitate disconnection of thegas turbine engine 25 during removal of the DDU 23 from the enclosure21. Further, such connections such as fuel lines and hydraulic lines mayrun to a single bulkhead (not shown) within or near the enclosure toallow for quick disconnection by locating these connections in a commonlocation.

FIG. 4 is a side elevation view of the DDU 23 as viewed from the lateralside 55 of the enclosure 21, with the DDU being mounted on a DDUpositioner assembly or DDU positioning system 101 (FIGS. 4-6C) forpositioning the DDU for withdrawal or removal from the enclosure throughthe access doors 45. In one embodiment, the DDU positioner assembly 101comprises a platform 103 slidably mounted to overlie two lateral rails105, 107 mounted to overlie the floor 41 of the enclosure 21 andextending laterally across the enclosure generally between the lateralsides 55, 57. The DDU positioner assembly 101 comprises two longitudinalrails 109, 111 mounted to overlie the platform 103 and extending in thelongitudinal direction L1. The DDU 23 is slidably mounted on thelongitudinal rails 109, 111 for positioning the DDU in the longitudinaldirection L1. In one embodiment, the DDU positioner assembly 101includes lateral guide rollers 115, 117 mounted on a respective lateralrail 105, 107, and longitudinal guide rollers 121, 123 mounted on arespective longitudinal rail 109, 111. The platform 103 is connected tothe lateral guide rollers 115, 117 to allow slidable movement andpositioning of the DDU 23 mounted on the platform in the lateraldirection L2 via the lateral rails 105, 107. The longitudinal guiderollers 121, 123 are connected to a mounting base 127 of the gearbox 27to allow slidable movement and positioning of the DDU 23 in thelongitudinal direction L1 via the longitudinal rails 109, 111. In oneembodiment, the DDU positioner assembly 101 includes four lateral guiderollers 115, 117 and four longitudinal guide rollers 121, 123, but moreor less than eight guide rollers may be provided without departing fromthe scope of the disclosure. Further, more or less than two longitudinalrails 109, 111, and more or less than two lateral rails 105, 107 may beprovided without departing from the scope of the disclosure. In oneembodiment, the guide rollers 115, 117, 121, 123 may be a caged balltype linear motion (LM) Guide, model number SPS20LR available from THKAmerica Inc., or any similar make or model number without departing fromthe scope of the disclosure. The DDU positioner assembly 101 may beequipped with locking mechanisms 128 mounted on a respective guideroller 115, 117, 121, 123. The locking mechanisms 128 may be springloaded and will default to the locked position to allow the DDU 23 to besecured in the operating position. The locking mechanism 128 may beotherwise located on the positioning system 101 without departing fromthe disclosure.

Exemplary loading calculations for sizing the guide rails 105, 107, 109,111 are shown below and are based on the Vericor TF50F turbineparameters as follows: approximate turbine weight, 1475 lbs.;approximate fuel system weight, 85 lbs.; approximate gearbox weight,4000 lbs.; for a total approximate weight of 5559 lbs. Various otherparameters may be applicable based on the make, model, and size of thegas turbine engine 25.

Because of the arrangement the direct drive unit 23 including the gasturbine engine 25 cantilever mounted onto the gearbox 27 and extendingin the longitudinal direction L1 from the gearbox, there is added loadput onto the rear lateral guide rollers 115 and the rear longitudinalguide rollers 121, 123 (the guide rollers mounted closest to the gasturbine engine). Accordingly, an increased load rating may be applied tothe rear guide rollers 115, 121, 123 if required. The calculation of thecantilever load and the reaction forces may be calculated with theformulas shown below, which may also be used for further design andimplementation of the disclosed removal mechanisms.

Maximum Reaction at the fixed end may be expressed as: R_(A)=qL.

where: R_(A)=reaction force in A (N, lb), q=uniform distributed load(N/m, N/mm, lb/in), and

L=length of cantilever beam (m, mm, in).

Maximum Moment at the fixed end may be expressed as M_(A)=−q L²/2

Maximum Deflection at the end may be expressed as δ_(B)=q L⁴/(8 E I).

where: δ_(B)=maximum deflection in B (m, mm, in).

In one embodiment, the longitudinal guide rollers 121, 123 connected tothe support structure 127 of the gearbox 27 are positioned between eachpair of the lateral guide rollers 115, 117 to ensure equal weightdistribution over the platform 103 and to avoid cantilever loading theplatform. Different configurations of platforms, sliders, rails andmounts are contemplated and considered within the scope of thedisclosure. The configurations of the DDU positioner assembly 101 mayvary to suit a particular DDU 23 with various alternative combinationsof makes, model, and sizes of the gas turbine engine 25 and the gearbox27.

In one embodiment, the guide rails 105, 107, 109, 111 are made from asteel composition that has been mill finished and shot blasted toprotect the rail from the high heat environment within the turbineenclosure 21 and ensure strength retention under the exposedtemperatures. In one embodiment, the platform 103 is constructed out ofa composite material; however, other materials are contemplated andconsidered within the scope of the disclosure, such as but not limitedto, steel or stainless steel. The guide rails 105, 107, 109, 111,platform 103, and/or other components of the DDU positioner assembly 101may be made of various other suitable materials without departing fromthe scope of the disclosure.

FIGS. 6A-6B illustrate an exemplary method of removing the direct driveunit 23 from the enclosure 21 utilizing the DDU positioner assembly 101.FIG. 6A shows the DDU 23 in a first/operating position for operationwith the pump 33 of the pumping unit 11. The method includes accessingthe enclosure 21 and disconnecting the gas turbine engine 25 from theair inlet ducting 37. The flanges 51, 53 may be disconnected from theair inlet ducting 37 and the expansion joints 61, 63 flexed to allowseparation of the DDU 23 from the air inlet ducting. The gas turbineengine 25 may be disconnected from the air exhaust ducting 35 bydisconnecting the exhaust duct flange 54 from the air exhaust ducting.Corresponding hoses, piping, wiring, and cabling including fuel lines,electrical lines, hydraulic lines, control lines or any other connectionthat is needed for operation of the gas turbine engine 25 may also bedisconnected so that the gas turbine engine is free to move withoutdamaging any of the operational connections needed for operation of thegas turbine engine. For example, the air bleed off valve ducting may beremoved from the turbine engine 25 and secured at a location free ofinterference with movement of the turbine engine. Alternatively, somehoses, piping, wiring, etc. may include enough slack or flexibility sothat the DDU 23 may be initially moved before complete disconnection ofthe connections from the gas turbine engine 25 are required for removalof the DDU from the enclosure 21. The gearbox 27 may be disconnectedfrom the driveshaft 31 by disconnecting the outlet flange 50 from thedriveshaft. In one embodiment, the driveshaft 31 may be a slip-fitdriveshaft allowing the driveshaft to contract to facilitatedisconnection from the DDU 23. In one embodiment, the driveshaft 31 maybe a 390. Series, GWB Model 390.80 driveshaft available DanaCorporation, or other suitable driveshaft. The gearbox 27 may bedisconnected from any other connections needed for operation of the DDU23 to obtain freedom of movement of the gearbox without damaging any ofthe operating connections.

Once the gas turbine engine 25 is disconnected from the respectiveconnections and the gearbox 27 is disconnected from the driveshaft 31,the DDU positioner assembly 101 is operated to position the direct driveunit 23 for withdrawal from the enclosure 21. As shown in FIG. 6B, theDDU 23 is positioned in a second position where the DDU is first movedin the longitudinal direction L1 in the direction of arrow A1 by slidingthe DDU along the longitudinal rails 109, 111. In one embodiment, priorto initial movement of the DDU 23 in the longitudinal direction L1, thelongitudinal locks 128 associated with the longitudinal guide rollers121, 123 must be released to allow the movement of the DDU in thelongitudinal direction. After the movement of the DDU 23 in thelongitudinal direction L1 to the second position, the longitudinal locks128 may be reengaged to lock the longitudinal guide rollers 121, 123 andprevent further or additional unwanted movement of the DDU 23 along thelongitudinal rails 109, 111, and the lateral locks 128 associated withthe lateral guide rollers 115, 117 may be disengaged to allow lateralmovement of the DDU 23. Next, the platform 103 may be moved to a thirdposition by moving in the lateral direction L2 in the direction of arrowA2 (FIG. 6C) by sliding movement of the lateral guide rollers 115, 117along the lateral guide rails 105, 107. The DDU 23 is mounted to theplatform 103 and moves with the platform in the lateral direction L2 tothe third position of FIG. 6C. As shown in FIGS. 3 and 5, the lateralguide rails 105, 107 may extend to the access doors 45 in either side55, 57 of the enclosure 21. In some embodiments, lateral guide railextensions 107′ (FIG. 5) may be used to extend outside of the enclosure21 to allow the platform 103 and DDU 23 to be slid out of the enclosureonto an adjacent supporting structure or vehicle (e.g., maintenanceinspection platform or other suitable structure), or the platform 103and DDU 23 may be accessed through the access doors 45 of the enclosure21 by a lifting mechanism (e.g., a forklift, crane, or other suitablelifting mechanism) to fully remove the DDU from the enclosure. Thevarious method steps described herein for the method of positioning orremoving the DDU 23 may be otherwise performed in an alternative orderor simultaneously, or more or less steps may be used without departingfrom the scope of the disclosure.

FIGS. 7-10 illustrates a second embodiment of a DDU positioner assemblyor system 201 for positioning the direct drive unit 23 housed in theenclosure 21. In the illustrated embodiment, the DDU 23 includes a gasturbine engine 25 and a gearbox 27 identical to the first embodiment ofthe disclosure, but the DDU positioner assembly 201 may be used toposition a DDU that is alternatively configured without departing fromthe disclosure. As such, like or similar reference numbers will be usedto describe identical or similar features between the two embodiments.

In one embodiment, the DDU positioner assembly 201 includes a platform203 that supports the gearbox 27 and has a top surface 205, a bottomsurface 207, two sides 208, and two ends 210. The gearbox 27 is fixedlymounted to the top surface 205 of the platform 203. The platform 203 isslidably mounted on the base 41 of the enclosure 21 with the bottomsurface 207 of the platform being in slidable engagement with the floorof the enclosure. In a first or operating position (FIGS. 7 and 8A) ofthe direct drive unit 23, the platform 203 is fixedly attached to thebase 41 by a plurality of fasteners 211. Upon removal of the fasteners211, the platform 203 is capable of slidable movement with respect tothe base 41. The platform 203 is connected to the support structure 127of the gearbox 27 so that the drive unit 23 moves with the platform. Inone embodiment, the platform 203 has two lifting openings 215, 217extending between respective sides 208 of the platform. As shown in FIG.7, the lifting opening 215 towards the front of the gearbox 27 (closestto the drive shaft flange 50) is spaced a first distance D1 from acenterline CT of the gearbox and the lifting opening 217 towards therear of the gearbox (closest to the gas turbine engine 25) is spaced asecond distance from the centerline CT of the gearbox, with the distanceD2 being greater than the distance D2. The rear lifting opening 217 isfarther from the centerline CT of the gearbox 27 because of thecantilever mounted gas turbine engine 25 that shifts the center ofgravity of the DDU 23 from the centerline CT of the gearbox in thelongitudinal direction toward the gas turbine engine. The platform 203may be otherwise configured and/or arranged without departing from thescope of the disclosure.

In one embodiment, the DDU positioner assembly 201 includes a lubricatoror lubrication system 221 (FIG. 9) to convey lubricant (e.g., grease orother suitable lubricant) from a lubricant reservoir 244 to a locationbetween the bottom surface 207 of the platform 201 and the base 41 ofthe enclosure. The DDU positioner assembly 201 includes a lubricationportion 225 (FIG. 10) of the base 41 below the platform 203. As shown inFIG. 10, the portion 225 of the base 41 includes a plurality oflubrication grooves 227. The lubrication grooves 227 are in fluidcommunication with the lubricator 221 so that the lubricator provideslubricant to the grooves to facilitate sliding engagement between theplatform 203 and the portion 225 of the base 41. The lubricator 221includes a source of lubricant 244, tubing 243, and other requiredcomponents (e.g., pump, controls, etc.) for delivering the lubricant tothe lubrication portion 225 at a sufficiently high pressure forlubricant to fill the grooves 227 of the lubrication portion 225. In oneembodiment, the lubricator 221 may be an automatic lubricator such as amodel TLMP lubricator available from SKF Corporation, or the lubricatormay be any other suitable lubricator including other automaticlubricators or manual lubricators without departing from the scope ofthe disclosure. In one embodiment, the lubrication portion 225 of thebase 41 is an integral portion with the base or the floor of theenclosure 21, but the lubrication portion 225 may be a separate pad orcomponent that is mounted between the base and the platform withoutdeparting from the disclosure. The lubricator 221 may be mounted insidethe enclosure 21 or at least partially outside the enclosure withoutdeparting from the scope of the disclosure.

In one embodiment, the DDU positioner assembly 201 includes drivefasteners 241 mounted at one end 210 of the platform 203. In theillustrated embodiment, the drive fasteners 241 include a bracket 245mounted to the floor 41 of the enclosure 21 and an impact screw 247operatively connected to the bracket and the platform 203. The drivefasteners 241 may have other components and be otherwise arrangedwithout departing from the disclosure. Further, more or less than twodrive fasteners 241 may be provided without departing from thedisclosure.

FIGS. 8A-9 illustrate an exemplary method of removing the DDU 23 fromthe enclosure 21 utilizing the DDU positioner assembly 201 of the secondembodiment. The method is similar to the method of the first embodiment,in that the gas turbine engine 25 is disconnected from the air inletducting 37, the air exhaust ducting 35, and from other correspondingconnections and components in a similar manner as discussed above forthe first embodiment so that the gas turbine engine is free to movewithout damaging any of the operational connections and componentsneeded for operation of the gas turbine engine. Further, the gearbox 27is disconnected from the driveshaft 31 in a similar manner as the firstembodiment, so that the DDU 23 has clearance for movement in thelongitudinal direction L1 without interference with the driveshaft.

FIG. 8A shows the direct drive unit 23 in the first/operating position.Once the gas turbine engine 25 is disconnected from the respectivecomponents and connections and the gearbox 27 is disconnected from thedriveshaft 31 and any other connections, the DDU positioner assembly 201is operated to position the DDU 23 for withdrawal from the enclosure 21.First, the fasteners 211 fixedly attaching the platform 203 to the base41 are removed. The lubricator 221 is operated to convey lubricant tothe lubrication grooves 227 of the lubrication portion 225 of the base41. After a sufficient amount of lubrication is located between theplatform 203 and the lubrication portion 225 of the base 41, the drivefasteners 241 may be operated to move the platform 203 in thelongitudinal direction L1 to a second position (FIG. 8B). As the impactscrews 247 of the drive fasteners 241 are turned, the platform 203 isslid in the longitudinal direction L1 in the direction of arrow A3 (FIG.8B). The lubricant provided in the lubrication grooves 227 and betweenthe lubrication portion 225 and the bottom surface 207 of the platformreduces the sliding friction and allows the rotation of the impactscrews 247 in the bracket 245 to advance the platform in the directionof arrow A3. The platform 203 is moved in the direction of arrow A3 asufficient amount to allow access to the lifting openings 215, 217 by alifting mechanism (e.g., forklift) 261 (FIG. 8C). The lifting mechanism261 may include a forklift or other lifting mechanism that may accessthe interior 46 of the enclosure through the enclosure access doors 45.The lifting mechanism 261 is inserted into the lifting openings 215, 217of the platform 203, and the DDU 23 is lifted and/or slid in thedirection of arrow A4. The lifting mechanism 261 may move the DDU 23 tothe third position (FIG. 8C), or transfer the DDU onto an adjacentsupporting structure or vehicle (e.g., maintenance inspection platformor other suitable structure), or completely remove the platform 203 andDDU 23 from the enclosure. The various method steps described herein forthe method of positioning or removing the DDU 23 by operating the DDUpositioner assembly 201 may be otherwise performed in an alternativeorder or simultaneously, or more or less steps may be used withoutdeparting from the scope of the disclosure.

FIGS. 11-12C illustrate a third embodiment of a DDU positioner assemblyor system 301 for positioning the direct drive unit 23 housed in theenclosure 21. In the illustrated embodiment, the DDU 23 includes a gasturbine engine 25 and a gearbox 27 identical to the first and secondembodiments of the disclosure, but the DDU positioner assembly 301 maybe used to position a DDU that is alternatively configured withoutdeparting from the disclosure as will be understood by those skilled inthe art. The DDU positioner assembly 301 is generally similar to the DDUpositioner assembly 201 of the second embodiment, except the drivefasteners 241 have been removed and an actuator 341 is added to the DDUpositioner assembly of the third embodiment. As such, like or similarreference numbers will be used to describe identical or similar featuresbetween the second and third embodiments.

As shown in FIG. 11, the DDU positioner assembly 301 includes theactuator 341 that has a first end 345 connected to the base 41 of theenclosure 21 and a second end 347 connected to the end 210 of theplatform 203. In one embodiment, the actuator 341 is a hydrauliccylinder that has a piston rod 351 that is extendible from a cylinderbody 349 upon operation of the actuator. The actuator 341 may becontrolled by a manual control valve or the actuator may be configuredfor remote operation by connection to corresponding automated controlvalves. In the illustrated embodiment, one actuator 341 is shown, butthe DDU positioner assembly 301 may include more than one actuatorwithout departing from the scope of the disclosure. Further, theactuator 341 may be otherwise located for attachment to the platform 203without departing from the scope of the disclosure.

FIGS. 12A-12C illustrate an exemplary method of removing the DDU 23 fromthe enclosure 21 utilizing the DDU positioner assembly 301 of the secondembodiment. The method is similar to the method of the utilizing the DDUpositioner assembly 201 of the second embodiment, in that the gasturbine engine 25 is disconnected from the air inlet ducting 37, the airexhaust ducting 35, and from other corresponding connections andcomponents in a similar manner as discussed above for the firstembodiment so that the gas turbine engine is free to move withoutdamaging any of the operational connections and components needed foroperation of the gas turbine engine. Further, the gearbox 27 isdisconnected from the driveshaft 31 in a similar manner as the firstembodiment, so that the DDU 23 has clearance for movement in thelongitudinal direction L1 without interference with the driveshaft.Also, the DDU positioner assembly 301 of the third embodiment includesthe lubricator 221 (FIG. 9) for providing lubrication to lubricationgrooves 227 of the lubrication portion 225 of the base 41 to facilitatesliding of the platform 203 in the longitudinal direction L1, so thatthe DDU positioner assembly of the third embodiment operates in asimilar manner as the DDU positioner assembly 201 of the secondembodiment.

FIG. 12A shows the direct drive unit 23 in the first/operating position.Once the gas turbine engine 25 is disconnected from the respectivecomponents and connections, and the gearbox 27 is disconnected from thedriveshaft 31 and any other connections, the DDU positioner assembly 301is operated to position the DDU 23 for withdrawal from the enclosure 21.First, the fasteners 211 fixedly attaching the platform 203 to the base41 are removed. The lubricator 221 is operated to convey lubricant tothe lubrication grooves 227 of the lubrication portion 225 of the base41. After a sufficient amount of lubrication is located between theplatform 203 and the lubrication portion 225 of the base 41, theactuator 341 may be operated to move the platform 203 in thelongitudinal direction L1 to a second position (FIG. 12B). The extensionof the piston rod 351 of the actuator 341 exerts a force on the platform203 to slide the platform in the longitudinal direction L1 in thedirection of arrow A3 (FIG. 12B). The lubricant provided in thelubrication grooves 227 and between the lubrication portion 225 and thebottom surface 207 of the platform reduces the sliding friction andallows the actuator 341 to advance the platform in the direction ofarrow A3. As with the previous embodiment, the platform 203 is moved inthe direction of arrow A3 a sufficient distance to allow access to thelifting openings 215, 217 by a lifting mechanism (e.g., forklift) 261(FIG. 8C). The lifting mechanism 261 may include a forklift or otherlifting mechanism that may access the interior 46 of the enclosurethrough the enclosure access doors 45. The lifting mechanism 261 isinserted into the lifting openings 215, 217 of the platform 203, and theDDU 23 is lifted and/or slid in the direction of arrow A4. Prior tomoving the platform 203 in the direction of arrow A4, the actuator 341may be disconnected from the platform (FIG. 12C) with the first end 347of the actuator being separated from the platform and the second end 345of the actuator remaining attached to the floor 41 of the enclosure.Alternatively, the second end 345 of the actuator 341 may bedisconnected from the floor 41 of the enclosure and the first end 341 ofthe actuator may remain attached to the platform 203, or both ends ofthe actuator may be disconnected and the actuator removed withoutdeparting from the enclosure.

The lifting mechanism 261 may move the DDU 23 to the third position(FIG. 12C), or transfer the DDU onto an adjacent supporting structure orvehicle (e.g., maintenance inspection platform or other suitablestructure), or completely remove the platform 203 and DDU 23 from theenclosure. The various method steps described herein for the method ofpositioning or removing the DDU 23 by operating the DDU positionerassembly 301 may be otherwise performed in an alternative order orsimultaneously, or more or less steps may be used without departing fromthe scope of the disclosure.

Having now described some illustrative embodiments of the disclosure, itshould be apparent to those skilled in the art that the foregoing ismerely illustrative and not limiting, having been presented by way ofexample only. Numerous modifications and other embodiments are withinthe scope of one of ordinary skill in the art and are contemplated asfalling within the scope of the disclosure. In particular, although manyof the examples presented herein involve specific combinations of methodacts or system elements, it should be understood that those acts andthose elements may be combined in other ways to accomplish the sameobjectives. Those skilled in the art should appreciate that theparameters and configurations described herein are exemplary and thatactual parameters and/or configurations will depend on the specificapplication in which the systems and techniques are used. Those skilledin the art should also recognize or be able to ascertain, using no morethan routine experimentation, equivalents to the specific embodiments ofthe disclosure. It is, therefore, to be understood that the embodimentsdescribed herein are presented by way of example only and that, withinthe scope of any appended claims and equivalents thereto; theembodiments of the disclosure may be practiced other than asspecifically described.

Furthermore, the scope of the present disclosure shall be construed tocover various modifications, combinations, additions, alterations, etc.,above and to the above-described embodiments, which shall be consideredto be within the scope of this disclosure. Accordingly, various featuresand characteristics as discussed herein may be selectively interchangedand applied to other illustrated and non-illustrated embodiment, andnumerous variations, modifications, and additions further may be madethereto without departing from the spirit and scope of the presentdisclosure as set forth in the appended claims.

What is claimed is:
 1. A direct drive unit (DDU) removal system, thesystem comprising: an enclosure housing a DDU, the DDU including agearbox and a turbine engine connected to the gearbox to drive adriveshaft connected to a pump for use in high-pressure, high-powerhydraulic fracturing operations, a DDU positioner assembly positioningthe DDU housed in the enclosure and facilitating removal of the DDU fromthe enclosure, the DDU positioner assembly comprising: a plurality oflongitudinal rails extending in a longitudinal direction along a centralaxis of the DDU; a plurality of lateral rails extending in a lateraldirection transverse to the longitudinal direction and mounted to afloor of the enclosure; and a platform slidably connected to theplurality of lateral rails and having the plurality of longitudinalrails mounted thereon so that the DDU slidably connects to thelongitudinal rails when positioned thereon thereby defining aDDU-mounted platform, the DDU being movable in the longitudinaldirection along the longitudinal rails to longitudinally position theDDU within the enclosure, and the DDU-mounted platform movable in thelateral direction along the lateral rails to remove the DDU-mountedplatform from the enclosure.
 2. The DDU positioner assembly of claim 1,further comprising a plurality of lateral guide rollers slidablyconnecting the platform to a respective lateral rail of the plurality oflateral rails and a plurality of longitudinal guide rollers to slidablyconnect the DDU to a respective longitudinal rail of the plurality oflongitudinal rails.
 3. The DDU positioner assembly of claim 2, whereinthe plurality of longitudinal guide rollers is positioned longitudinallybetween the plurality of lateral guide rollers.
 4. The DDU positionerassembly of claim 3, wherein the platform is mounted to overlie theplurality of lateral guide rollers, and wherein the plurality oflongitudinal rails is mounted to overlie the platform.
 5. The DDUpositioner assembly of claim 4, wherein the plurality of longitudinalguide rollers is configured to connect to the gearbox when positionedadjacent thereto.
 6. The DDU positioner assembly of claim 4, furthercomprising a plurality of locking mechanisms for locking the platform ina fixed position on the plurality of lateral rails and the plurality oflongitudinal rails.
 7. The DDU positioner assembly of claim 2, whereinthe platform is configured to connect to a support of the gearbox whenpositioned adjacent thereto, and the turbine engine is mounted to thegearbox and extends in the longitudinal direction from the gearbox.